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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8c0209f84796314bf48de9bfcc3808d506003c5b5e0609984bace5f8728ba23' 
  AND token = 'W0wKn73itKb26NtCyKhZo8DMwFFumC9kYqA3hDDPyxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}